Re: [PATCH 3/3] IB/multicast: Check ib_find_pkey() return value

[Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

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On Mon, Nov 21, 2016 at 10:22:17AM -0800, Bart Van Assche wrote:
> This patch avoids that Coverity complains about not checking the
> ib_find_pkey() return value.
>
> Fixes: commit 547af76521b3 ("IB/multicast: Report errors on multicast groups if P_key changes")
> Signed-off-by: Bart Van Assche <bart.vanassche-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
> Cc: Sean Hefty <sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Cc: <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
> ---
>  drivers/infiniband/core/multicast.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/infiniband/core/multicast.c b/drivers/infiniband/core/multicast.c
> index e51b739..322cb67 100644
> --- a/drivers/infiniband/core/multicast.c
> +++ b/drivers/infiniband/core/multicast.c
> @@ -518,8 +518,11 @@ static void join_handler(int status, struct ib_sa_mcmember_rec *rec,
>  		process_join_error(group, status);
>  	else {
>  		int mgids_changed, is_mgid0;
> -		ib_find_pkey(group->port->dev->device, group->port->port_num,
> -			     be16_to_cpu(rec->pkey), &pkey_index);
> +
> +		if (ib_find_pkey(group->port->dev->device,
> +				 group->port->port_num, be16_to_cpu(rec->pkey),
> +				 &pkey_index))
> +			pkey_index = MCAST_INVALID_PKEY_INDEX;

The coverity warning is valid, ib_find_pkey() can return ENOMEM
(ib_find_pkey()->ib_query_pkey()->(device->query_pkey())->mlx5_ib_query_pkey()->mlx5_query_mad_ifc_pkey()/mlx5_query_hca_vport_pkey())

I'm not sure that the error handling proposed is enough, pkey_index is initialized to
MCAST_INVALID_PKEY_INDEX at the beginning of function and in case of error it preserves
its value.

Don't you need to update process_group_error() function? It has code
flows with ib_find_pkey() without checking return value, which can be
anything too.

Thanks

>
>  		spin_lock_irq(&group->port->lock);
>  		if (group->state == MCAST_BUSY &&
> --
> 2.10.2
>
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